This exercise has individual determine the number of triangles in a diagram. Then it asks for two individuals to do the same thing and come up with a total number of triangles that they agree on. The third part of the activity groups four students together and asks them to reach concensus on the number of triangles in the figure. The debrief on this exercise show the class how much closer to the best answer is delivered by the group. The range of answers is usually very wide when individuals do it alone as opposed to a much smaller range when the groups submt their answers.